Date: Thu 18 Aug 1988 02:13-EDT From: AIList Moderator Nick Papadakis Reply-To: AIList@mc.lcs.mit.edu Us-Mail: MIT LCS, 545 Tech Square, Rm# NE43-504, Cambridge MA 02139 Phone: (617) 253-6524 Subject: AIList Digest V8 #54 To: AIList@mc.lcs.mit.edu Status: R AIList Digest Thursday, 18 Aug 1988 Volume 8 : Issue 54 Philosophy: Human symbol processing Navigation and symbol manipulation Can we human being think two different things in parallel? The Godless assumption ---------------------------------------------------------------------- Date: Sun, 14 Aug 88 13:57:17 -0200 From: Antti Ylikoski Subject: human symbol processing In AIList Digest V8 #47, jbn@glacier.stanford.edu (John B. Nagle) writes: >Antti Ylikoski (YLIKOSKI@FINFUN.BITNET) writes: >>I once heard an (excellent) talk by a person working with Symbolics. >>(His name is Jim Spoerl.) >> >>One line by him especially remained in my mind: >> >> ... >> >>A very typical example of the human real-time symbol processing is >>what happens when a person drives a car. Sensory input is analyzed >>and symbols are formed of it: a traffic sign; a car driving in the >>same direction and passing; the speed being 50 mph. There is some >>theory building going on: that black car is in the fast lane and >>drives, I guess, some 10 mph faster than me, therefore I think it's >>going to pass me after about half a minute. To a certain extent, the >>driver's behaviour is rule-based: there is for example a rule saying >>that whenever you see a red traffic light in front of you you have to >>stop the car. (I remember someone said in AIList some time ago that >>rule-based systems are "synthetic", not similar to human information >>processing. I disagree.) > > As someone who works on automatic driving and robot navigation, >I have to question this. One notable fact is that animals are quite >good at running around without bumping into things. Horses are capable >of running with the herd over rough terrain within hours of birth. >("Horses of the Camargue" has some beautiful pictures of this.) This >leads one to suspect that the primary mechanisms are not based on >symbols or rules. Definitely, learning is not required. Horses are >born with the systems for walking, obstacle avoidance, running, standing up, >motion vision, foot placement, and small-obstacle jumping fully functional. > > ... > >In real-world situations, as faced by robots, the processing necessary >to put the sensory data into a form where rule-based approaches can even >begin to operate is formidable, and in most non-trivial cases is beyond >the state of the art. > > ... > >Personally, I suspect that horse-level performance in navigation and >squirrel-level performance in manipulation can be achieved without any >component of the system using mathematical logic. I won't disagree. I expressed my thoughts badly; my point was that driving a car is a different activity from a horse running over uneven terrain, and it requires symbol processing, even if animals can navigate without logic. Driving a car could perhaps be described as a combination of already existing geometric etc. reasoning capabilities and learned symbol processing skills. --- Andy Ylikoski ------------------------------ Date: Mon, 15 Aug 88 07:08:54 PDT From: Stephen Smoliar Subject: navigation and symbol manipulation John Nagle offered the following observations: > I would encourage people moving into the AI field to work in the > vision, spatial, and geometric domains. There are many problems that > need to be solved, and enough computational power is becoming available > to address them. Much of the impetus for the past concentration on highly > abstract domains came from the need to find problems that could be > addressed with modest computational resources. This is much less of a > problem today. We are beginning to have adequate tools. > > Personally, I suspect that horse-level performance in navigation > and squirrel-level performance in manipulation can be achieved without > any component of the system using mathematical logic. It is also worth noting that Chapter 8 of Gerald Edelman's NEURAL DARWINISM includes a fascinating discussion of the possible role of interaction between sensory and motor systems. I think it is fair to say that Edelman shares Nagle's somewhat jaundiced view of mathematical logic, and his alternative analysis of the problem makes for very interesting, and probably profitable, reading. ------------------------------ Date: Mon, 15 Aug 88 09:26:06 PDT From: norman%ics@ucsd.edu (Donald A Norman-UCSD Cog Sci Dept) Reply-to: danorman@ucsd.edu Subject: Can we human being think two different things in parallel? The question is: Can we human being think two different things in parallel? the answer is, it all depends you what you mean. This is one of my research areas, so let me try an answer. There is a vast literature in psychology on the topic of simultaneous activity (the area is called the field of "attention.") But the question is ill-formed, for to answer it requires the definition of three terms, none of which are well defined: think What do you mean by "think"? Any mental activity? Well, clearly we can normally walk and talk at the same time, but if I am walking over a slippery, dangerous mountain peak, I can't: I have to stop talking. And I can listen to you and watch television. And I can shadow text coming in one ear (a old, once favorite experimental method) while doing visual tasks at the same time, but failing to do verbal tasks. thing What constitutes separate things. If the things are on closely related topics, are they separate? If I do mental multiplication, is keeping track of the carrys (a working memory task) a separate thing than doing the table-look up for the products, or from telling you what I am doing? Of if I am thinking about tomorrow's dinner, is that different than navigating my car through heavy traffic (both require decision making, memory, and planning). "in parallel." There are lots of ways of doing things in parallel, depending upon your deffinition. Rapid time switching (round-robin time sharing) or independent processing circuits. Not clear which the human does -- probably both. But there is probably interaction among the things done in parallel, so that for many combinations of tasks, although they are indeed done at the same time, at least one is done more slowly, less efficiently, or with more errors than were it being done alone-- so how does this qualify in answer to the question. Note that connectionist circuits so far only do one task at a time, and serially (that is, they can settle into only one meaningful state at any one time), although they do that task in a highly parallel fashion. This again, shows the dificulty of interpreting the question. So, the question is ill formed and maybe unanswerable. There are, however, clear and unmistakable limits on how much a person can do consciously at any one time. But if the skill is highly practiced, it becomes "automated" and can then evidently be done at the same time as other things, with either no degradation in either task, or only small degradation. If I do 2 things at once, and one is degraded as a result, is this 2 things in parallel? don norman (Schedule: I will be away Aug 17 - Sep 2 -- mostly at the International Congress of Psychology in Sydney, Australia.) Donald A. Norman Department of Cognitive Science C-015 University of California, San Diego La Jolla, California 92093 INTERNET: danorman@ucsd.edu INTERNET: norman@ics.ucsd.edu BITNET: danorman@ucsd.bitnet UNIX:{decvax,ucbvax,ihnp4}!sdcsvax!ics!norman (If you reply directly to me, please include your postal mail address and all possible e-mail addresses. I often can't answer people because their e-mail paths fail.) ------------------------------ Date: 15 Aug 88 11:53 PDT From: hayes.pa@Xerox.COM Subject: Re: think two different things in parallel YWLee writes >Can we human being think two different things in parallel?.. >One of my friends said that there should be no problem > in doing that. It all depends on what your friend meant by `think'. In one sense, we are thinking lots of things in parallel all the time. For example, visual processing is going on ( when your eyes are open ) while you are choosing a form of words to express what you want to communicate, and something in your head is listening as well, because if you hear a tiger roar behind you, you will move really fast. Even quite simple skills seem to require whole lots of parallel mental activity. You probably didnt mean that, though: you meant something more like the intuitive sense of think. I dont think we have any clear account of what that amounts to in terms of cognitive machinery. But in any case, you wouldnt get the answer to the question by considering the structure of brains. The brain is clearly a highly parallel machine, but that doesnt entail anything about the structure of conscious thought. Pat Hayes ------------------------------ Date: Mon 15 Aug 88 14:20:03-PDT From: Mike Dante Subject: Re: The Godless assumption. I am more than a little surprised by Marvin Minsky's ad hom attack on Andrew Basden. Would it be equally fair to turn the argument around and replace "religion" with "science"? For example, would Dr. Minsky feel that his support for science can be fairly attacked by saying: >Yes, enough to justify what those who "knew" that they were right did >to the Kulaks in the name of "Scientific" socialism, or the atrocities >carried out by Nazi "scientists" on concentration camp victims. There is >no question that people's beliefs have practical consequences; or did >you mean to assert that, in your philosophical opinion, they simply >may have been perfectly correct? I would hope, that on second thought, Dr. Minsky might agree that Andrew Basden is no more responsible for burning Bruno than Marvin Minsky is for experimenting on Jews. And even more, that neither religion nor science has any justification for being self righteous. Both science and religion have been used to justify atrocities. I don't see that as any excuse for being a Luddite in either field. ------------------------------ Date: Wed, 17 Aug 88 09:24 CDT From: T. Michael O'Leary Subject: Assumptions >Science, though not scientists (unfortunately), rejects the >validity of religion: it requires that reality is in some sense >utterly lawful, and that the unlawful, i.e. god, has no place. To me this requirement is unnecessarily strict. Science does not require that reality be utterly lawful, but merely that it be possible for scientists to observe patterns in nature. When asked (apparently by Napoleon) where God fit into his equations, Laplace is said to have replied, "I have no need of that hypothesis." To my way of thinking, if he had been confronted by the assertion of Mr. Wells shown above, his reply should have been the same. Michael O'Leary ------------------------------ End of AIList Digest ********************